Doesn't one of those 1-click root apps also have an "unroot" button?
Anyway, what's the point of rooting now if you plan on getting the OTA update? With all probability, the OTA update will make you lose root anyway. If you want to be permanently rooted, then you might as well just go all the way by rooting now, denying the OTA update, and using Bootstrap to install new ROMS when they come out.
If getting the OTA update is more important to you than being rooted, then you might as well leave things alone and wait for the update. If we weren't so close to the OTA update, then it would make sense to root now. But nobody knows for sure what's going to happen to rooters when the OTA update comes out.
So my suggestion is to either wait it out or totally jump in. Personally, I totally jumped in and do NOT want the official OTA update. I will wait for custom ROMs and install them myself. For example, mrbirdman is supposedly releasing a version very soon:
"FlyX - Deodexed, optimized, bloat removed, froyo update.zip coming soon to a DX near you...."
And then, he plans to release a vanilla Froyo version about a week later:
"the full vanilla rom will be much nicer than this...but its gonna be a week or so before thats ready."
So you have to decide what's more important to you: having an "official" OTA update or keeping root and having totally control over your phone!